[PATCH v13 12/85] KVM: Drop @atomic param from gfn=>pfn and hva=>pfn APIs

[Sean Christopherson <seanjc@google.com>]

Drop @atomic from the myriad "to_pfn" APIs now that all callers pass
"false", and remove a comment blurb about KVM running only the "GUP fast"
part in atomic context.

No functional change intended.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 Documentation/virt/kvm/locking.rst     |  4 +--
 arch/arm64/kvm/mmu.c                   |  2 +-
 arch/powerpc/kvm/book3s_64_mmu_hv.c    |  2 +-
 arch/powerpc/kvm/book3s_64_mmu_radix.c |  2 +-
 arch/x86/kvm/mmu/mmu.c                 | 12 ++++----
 include/linux/kvm_host.h               |  4 +--
 virt/kvm/kvm_main.c                    | 39 ++++++--------------------
 virt/kvm/kvm_mm.h                      |  4 +--
 virt/kvm/pfncache.c                    |  2 +-
 9 files changed, 23 insertions(+), 48 deletions(-)

diff --git a/Documentation/virt/kvm/locking.rst b/Documentation/virt/kvm/locking.rst
index 3d8bf40ca448..f463ac42ac7a 100644
--- a/Documentation/virt/kvm/locking.rst
+++ b/Documentation/virt/kvm/locking.rst
@@ -135,8 +135,8 @@ We dirty-log for gfn1, that means gfn2 is lost in dirty-bitmap.
 For direct sp, we can easily avoid it since the spte of direct sp is fixed
 to gfn.  For indirect sp, we disabled fast page fault for simplicity.
 
-A solution for indirect sp could be to pin the gfn, for example via
-kvm_vcpu_gfn_to_pfn_atomic, before the cmpxchg.  After the pinning:
+A solution for indirect sp could be to pin the gfn before the cmpxchg.  After
+the pinning:
 
 - We have held the refcount of pfn; that means the pfn can not be freed and
   be reused for another gfn.
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index a509b63bd4dd..a6e62cc9015c 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1569,7 +1569,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	mmu_seq = vcpu->kvm->mmu_invalidate_seq;
 	mmap_read_unlock(current->mm);
 
-	pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL,
+	pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
 				   write_fault, &writable, NULL);
 	if (pfn == KVM_PFN_ERR_HWPOISON) {
 		kvm_send_hwpoison_signal(hva, vma_shift);
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 1b51b1c4713b..8cd02ca4b1b8 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -613,7 +613,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_vcpu *vcpu,
 		write_ok = true;
 	} else {
 		/* Call KVM generic code to do the slow-path check */
-		pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL,
+		pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
 					   writing, &write_ok, NULL);
 		if (is_error_noslot_pfn(pfn))
 			return -EFAULT;
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 408d98f8a514..26a969e935e3 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -852,7 +852,7 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
 		unsigned long pfn;
 
 		/* Call KVM generic code to do the slow-path check */
-		pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL,
+		pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
 					   writing, upgrade_p, NULL);
 		if (is_error_noslot_pfn(pfn))
 			return -EFAULT;
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 5fe45ab0e818..0e235f276ee5 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4380,9 +4380,9 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 		return kvm_faultin_pfn_private(vcpu, fault);
 
 	async = false;
-	fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, false, false,
-					  &async, fault->write,
-					  &fault->map_writable, &fault->hva);
+	fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, false, &async,
+					  fault->write, &fault->map_writable,
+					  &fault->hva);
 	if (!async)
 		return RET_PF_CONTINUE; /* *pfn has correct page already */
 
@@ -4402,9 +4402,9 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	 * to wait for IO.  Note, gup always bails if it is unable to quickly
 	 * get a page and a fatal signal, i.e. SIGKILL, is pending.
 	 */
-	fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, false, true,
-					  NULL, fault->write,
-					  &fault->map_writable, &fault->hva);
+	fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, true, NULL,
+					  fault->write, &fault->map_writable,
+					  &fault->hva);
 	return RET_PF_CONTINUE;
 }
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 56e7cde8c8b8..2faafc7a56ae 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1232,9 +1232,8 @@ kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn);
 kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
 		      bool *writable);
 kvm_pfn_t gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn);
-kvm_pfn_t gfn_to_pfn_memslot_atomic(const struct kvm_memory_slot *slot, gfn_t gfn);
 kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
-			       bool atomic, bool interruptible, bool *async,
+			       bool interruptible, bool *async,
 			       bool write_fault, bool *writable, hva_t *hva);
 
 void kvm_release_pfn_clean(kvm_pfn_t pfn);
@@ -1315,7 +1314,6 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn);
 
 struct kvm_memslots *kvm_vcpu_memslots(struct kvm_vcpu *vcpu);
 struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn);
-kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn);
 kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn);
 int kvm_vcpu_map(struct kvm_vcpu *vcpu, gpa_t gpa, struct kvm_host_map *map);
 void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 957b4a6c9254..0bc077213d3e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2756,8 +2756,7 @@ static inline int check_user_page_hwpoison(unsigned long addr)
 
 /*
  * The fast path to get the writable pfn which will be stored in @pfn,
- * true indicates success, otherwise false is returned.  It's also the
- * only part that runs if we can in atomic context.
+ * true indicates success, otherwise false is returned.
  */
 static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
 			    bool *writable, kvm_pfn_t *pfn)
@@ -2922,7 +2921,6 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
 /*
  * Pin guest page in memory and return its pfn.
  * @addr: host virtual address which maps memory to the guest
- * @atomic: whether this function is forbidden from sleeping
  * @interruptible: whether the process can be interrupted by non-fatal signals
  * @async: whether this function need to wait IO complete if the
  *         host page is not in the memory
@@ -2934,22 +2932,16 @@ static int hva_to_pfn_remapped(struct vm_area_struct *vma,
  * 2): @write_fault = false && @writable, @writable will tell the caller
  *     whether the mapping is writable.
  */
-kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible,
-		     bool *async, bool write_fault, bool *writable)
+kvm_pfn_t hva_to_pfn(unsigned long addr, bool interruptible, bool *async,
+		     bool write_fault, bool *writable)
 {
 	struct vm_area_struct *vma;
 	kvm_pfn_t pfn;
 	int npages, r;
 
-	/* we can do it either atomically or asynchronously, not both */
-	BUG_ON(atomic && async);
-
 	if (hva_to_pfn_fast(addr, write_fault, writable, &pfn))
 		return pfn;
 
-	if (atomic)
-		return KVM_PFN_ERR_FAULT;
-
 	npages = hva_to_pfn_slow(addr, async, write_fault, interruptible,
 				 writable, &pfn);
 	if (npages == 1)
@@ -2986,7 +2978,7 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible,
 }
 
 kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
-			       bool atomic, bool interruptible, bool *async,
+			       bool interruptible, bool *async,
 			       bool write_fault, bool *writable, hva_t *hva)
 {
 	unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault);
@@ -3008,39 +3000,24 @@ kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
 		writable = NULL;
 	}
 
-	return hva_to_pfn(addr, atomic, interruptible, async, write_fault,
-			  writable);
+	return hva_to_pfn(addr, interruptible, async, write_fault, writable);
 }
 EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
 
 kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
 		      bool *writable)
 {
-	return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, false,
-				    NULL, write_fault, writable, NULL);
+	return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, NULL,
+				    write_fault, writable, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_prot);
 
 kvm_pfn_t gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn)
 {
-	return __gfn_to_pfn_memslot(slot, gfn, false, false, NULL, true,
-				    NULL, NULL);
+	return __gfn_to_pfn_memslot(slot, gfn, false, NULL, true, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot);
 
-kvm_pfn_t gfn_to_pfn_memslot_atomic(const struct kvm_memory_slot *slot, gfn_t gfn)
-{
-	return __gfn_to_pfn_memslot(slot, gfn, true, false, NULL, true,
-				    NULL, NULL);
-}
-EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic);
-
-kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn)
-{
-	return gfn_to_pfn_memslot_atomic(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
-}
-EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn_atomic);
-
 kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
 {
 	return gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn);
diff --git a/virt/kvm/kvm_mm.h b/virt/kvm/kvm_mm.h
index 715f19669d01..a3fa86f60d6c 100644
--- a/virt/kvm/kvm_mm.h
+++ b/virt/kvm/kvm_mm.h
@@ -20,8 +20,8 @@
 #define KVM_MMU_UNLOCK(kvm)		spin_unlock(&(kvm)->mmu_lock)
 #endif /* KVM_HAVE_MMU_RWLOCK */
 
-kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible,
-		     bool *async, bool write_fault, bool *writable);
+kvm_pfn_t hva_to_pfn(unsigned long addr, bool interruptible, bool *async,
+		     bool write_fault, bool *writable);
 
 #ifdef CONFIG_HAVE_KVM_PFNCACHE
 void gfn_to_pfn_cache_invalidate_start(struct kvm *kvm,
diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c
index f0039efb9e1e..58c706a610e5 100644
--- a/virt/kvm/pfncache.c
+++ b/virt/kvm/pfncache.c
@@ -198,7 +198,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc)
 		}
 
 		/* We always request a writeable mapping */
-		new_pfn = hva_to_pfn(gpc->uhva, false, false, NULL, true, NULL);
+		new_pfn = hva_to_pfn(gpc->uhva, false, NULL, true, NULL);
 		if (is_error_noslot_pfn(new_pfn))
 			goto out_error;
 
-- 
2.47.0.rc1.288.g06298d1525-goog